Journal of Applied Microscopy. 421 



ganglion, sense, and muscle cells. In this he contradicts the teachings of 

 Biitschli, Leydig, and others, and asserts that " nur Max Schultze und seine 

 Anhdnger habeti Recht in Betreff der feinereti histologischen Natur der Nerven- 

 fasene." 



Each nerve cell produces a number of elementary fibrils, and these unite to 

 form primitive fibrils, which divide themselves among the branches of the cell 



Multipolar motor cell of Lumbricus. P. Primitive fibril formed by union of the 

 neurofibrils of the cell. 



and extend to the centrum, where they enter the ganglion cells — usually through 

 the main process of the cell, although fine fibrils may enter at other points — and 

 break up within the somatoplasm into a fine network, the form and position of 

 which varies in different types of cells. No fibril passes through a cell without 

 branching and forming part of the network which surrounds the nucleus, but 

 never penetrates it or unites with any of its elements. The fibrils do not remain 

 in the cell, but unite to form a thicker primitive fibril, which may enter other 

 ganglion cells and form a network in them, and then pass on to a muscle. 

 In this way there is direct continuity between cellulipetal and cellulifugal fibrils. 



Peripherally, the nerve breaks up before it reaches the sensory cells, and 

 sends one primitive fibril to each cell (at least, in the worms and the molluscs). 

 Inside the sense cell, a plexus is formed around the nucleus, after which the 

 branches unite in a single fibril, which may pass out to the cuticle, or may take 

 an intercellular course in the sub-cuticula. 



A distinction is made between nerve and ganglion cells. The nerve cell is 

 structurally the analogy of the muscle cell, and produces conducting substance 

 just as the muscle cell produces contractile substance. The conducting sub- 

 stance consists, in the main, of the conducting primitive fibrils, just as the con- 

 tractile substance consists of contractile fibrils. Ganglion cells are, to a certain 

 degree, intercalated in the conducting nerve tracts, as current-generating elements 

 of the electric battery are inserted in the conducting path of telegraph wires. 



